Acrolein is a simple unsaturated aldehyde compound which includes incomplete reactive groups to have high reactivity, and is used as a major intermediate for synthesis of numerous chemicals. In particular, acrolein has been widely used as an intermediate for synthesis of acrylic acids, acrylic acid esters, superabsorbent polymers, animal feed supplements, or food supplements.
Such acrolein has been mainly prepared by selective gas-phase oxidation of a starting material, propylene, which is obtained during petroleum cracking with atmospheric oxygen. However, as fossil fuels have been reduced and environmental problems such as greenhouse effect have emerged, many studies have been conducted to develop a method of preparing acrolein using non-fossil fuel-based renewable materials.
Therefore, glycerin, which is a natural by-product obtained from biodiesel production has received much attention as a raw material for acrolein preparation. In particular, growth of biodiesel production increases the glycerin market, and industrial application of glycerin has been studied due to its low price.
For example, a method of obtaining acrolein by glycerin dehydration in the presence of a catalyst is known, in which an acid catalyst such as a zeolite, a phosphate, and tungstophosphoric acid (H3PW12O4) is used.
However, the previous catalysts used for the preparation of acrolein produce by-products such as hydroxyacetone, hydroxy propanone, propane aldehyde, acetaldehyde, acetone, and polycondensation products of glycerin, and thus there are limitations in their use for the preparation of acrolein with high purity.
Accordingly, there is a demand to develop a highly active catalyst system capable of minimizing by-product formation to increase selectivity and purity of acrolein and improving a conversion ratio and reaction yield of glycerin.